The invention relates to a valve with wider opening for a pressure regulator. The valves incorporated into pressure regulators allow slow pressure rises in the low-pressure circuit to be discharged and thus provide the installation situated downstream with fairly good protection.
The pressure rises are generally caused by dirt becoming lodged between the seat and the valve element.
In general, present-day valves are able to palliate this kind of fault.
However, safety problems may arise in pressure reducers for high-pressure compressed gas cylinders, generally for pressures ranging from 150 bar to 300 bar, or even beyond 300 bar.
Specifically, for these high pressures, the major risks, apart from the slow rises described hereinabove, are any sudden overpressures that may, by way of an exception, be caused by the pressure reducing valve element becoming jammed in the open position, following an operating defect such as a blockage or seizure.
In this case, the high-pressure gas arrives suddenly in the low-pressure chamber. If the valve does not react and open quickly enough and to a sufficient extent to remove this high-pressure gas, the regions customarily subjected to low pressure run the risk of not being able to withstand the pressure, and bursting may occur.
The standards regarding industrial pressure reducers or ones for medical gases incorporate the operating rules for these valves which are recalled, in particular, in document FR-A-9606925.
However, in the specific case of high throughput pressure reducers, existing valves do not open sufficiently to be able to absorb the high throughputs.
Furthermore, mention may be made of document WO-A-98/30859, which describes the gas pressure regulator for a paintball gun making it possible to reduce the pressure of a gas at high pressure. This device comprises a piston that can move in a chamber comprising three successive compartments, which piston is normally pushed back by a spring against a piston seat formed by the wall of the intermediate compartment. Because of the configuration of this device, the front face of the piston never comes into contact with the end wall of the upstream compartment into which the gas whose pressure is to be reduced enters, and this does not allow the valve to open wide enough in the event of a sudden increase in the amount of gas that is to be supplied.
Furthermore, mention may also be made of documents DE-A-1220688, WO-A-98/08012 and U.S. Pat. No. 2,655,936 which describe devices of crude design for regulating the pressure of a fluid.
It is therefore an object of the invention to produce a discharge valve incorporating the constraints set by international standards, to limit the abovementioned risks, while at the same time remaining of a simple design.
Stated in a different way, the present invention sets out to propose a quick-reacting discharge valve with wider opening, with an opening accuracy the adjustment of which does not slip, and which is extremely repeatable, more specifically intended for regulators for compressed gas cylinders or high-pressure medical or industrial pressure-reducing plant in which the throughput demand is high.
The solution afforded by the present invention is therefore a valve comprising:
a valve body comprising:
an internal chamber of axis (AA) comprising an upstream compartment and a downstream compartment, the said upstream compartment being of cylindrical cross section and of diameter (Dam) and the said downstream compartment being of cylindrical cross section and of diameter (Dav), with Dam less than Dav,
at least one fluid inlet orifice formed in the wall of the said valve body and opening into the upstream compartment of the internal chamber, and
at least one fluid outlet orifice, and
a piston body that can move in translation along the axis (AA) inside at least one part of the said internal chamber and is located between the said fluid inlet orifice and the said fluid outlet orifice, the said piston body having a front face located on the same side as the fluid inlet orifice, a rear face located on the same side as the fluid outlet orifice, and a lateral wall located between the said front face and the said rear face, the said lateral wall of the piston body having at least a first portion (P1) of cylindrical cross section and of first diameter (D1) and at least a second portion (P2) of cylindrical cross section and of second diameter (D2), with D1 less than D2 and D2 less than Dav,
and in which the wall of the said valve body has an internal face forming the end wall of the upstream compartment, against which face the front face of the piston body normally bears.
As the case may be, the valve of the invention may have the following characteristics:
the second diameter (D2) of the second portion (P2) is approximately equal to the diameter (Dam) of the valve body;
when the piston body moves in translation along the axis (AA) and in the direction that tends to move it away from the fluid inlet orifice, the second portion (P2) of the lateral wall of the piston body passes in succession from the upstream compartment to the downstream compartment of the internal chamber so as to open a space allowing fluid to flow between the lateral wall of the said second portion (P2) of the piston body and the wall internal to the downstream compartment of the internal chamber;
the front face of the piston body comprises sealing means;
part of the downstream compartment of the internal chamber comprises an elastic means which normally exerts a thrusting force on the rear face of the piston body, along the axis (AA) and in the direction that tends to bring the front face of the piston body closer to the internal face of the said valve body, the elastic means preferably being a spring;
at least one fluid inlet orifice opens onto the internal face of the upstream compartment, the fluid inlet orifice preferably opening towards the centre of the internal face;
the first portion (P1) of first diameter (D1) is located upstream of the second portion (P2) of second diameter (D2) when considering the direction in which a fluid flows as it passes in turn from the upstream compartment to the downstream compartment;
a sealing means is formed in the internal peripheral wall of the upstream compartment so as to provide a fluidic seal between the said upstream compartment and the said downstream compartment, when the second portion (P2) of the lateral wall of the piston body is positioned facing the said sealing means, the said sealing means preferably being an annular seal;
a leakage orifice is formed through the second portion (P2) of the lateral wall of the piston body so as to place the downstream compartment in fluidic communication with that part of the upstream compartment that is located between the said second portion (P2) of the lateral wall of the piston body and the front face of the piston body;
regulating means collaborate with the elastic means so that the thrusting force exerted on the rear face of the piston body can be regulated or adjusted;
it is formed of at least a first subunit and of a second subunit which are fixed together, the first subunit including at least the upstream compartment and at least one fluid inlet orifice, and the second subunit comprising at least one fluid outlet orifice, it preferably being possible for the two subunits to be fitted one inside the other.
According to another aspect, the invention also relates to a pressure regulating device making it possible to regulate or adjust the pressure of a fluid, particularly a gas, comprising such a valve.
According to yet another aspect, the invention relates to a pressure regulating device making it possible to regulate or adjust the pressure of a fluid, particularly a gas, comprising a main body comprising an internal fluid passage comprising a high-pressure fluid inlet and a low-pressure fluid outlet and means for reducing the pressure of the fluid being arranged, in a fluid pressure reducing chamber, between the said high-pressure fluid inlet and the said low-pressure fluid outlet, characterized in that the said fluid pressure reducing chamber is in fluidic communication with at least one fluid inlet orifice formed in the wall of a valve body and opening into the upstream compartment of the internal chamber of a valve according to the invention.
Furthermore, the invention also relates to a container for pressurized fluid, equipped with such a pressure regulating device, particularly a gas cylinder, or a pipe for pressurized fluid, equipped with such a pressure regulating device or with a valve according to the invention.